Grian's terrible, horrible, no good, very bad night

It’s well past midnight when Mumbo’s woken up by a knock at his door. Or, rather, by a tap against the outside of his campervan – the door is a solid three-dozen feet in the air now, thanks Grian, so it’s a little hard to knock. But he blinks himself into awakeness, squinting through the darkness and disorientation, and there’s another tap. They seem to be coming from the window.(In which Grian is an idiot, is terrifyingly competent, and needs a little midnight assistance. In that order. And also in which Mumbo is a good, if longsuffering, friend.)